Data were collected on the differences in weight gains of 12 people one

Question

month after they stopped smoking, compared with their weight at the time
when they stopped smoking. The data are given in Table 2. A positive
quantity corresponds to a gain in weight, a negative quantity toaloss.
Table 2
Person no. 1 234 5 6 789 10 11 12
Weight difference (kg) 1.0 2.3 −0.8 0.1 2.0 0.9 −0.3 2.4 −0.5 2.5 −1.3 2.1
A sign test is to be performed to investigate whether or not people gain
weight after stopping smoking.
(a) Write down the hypothesis to be tested. [1]
(b) Record the number of values lying above and the number lying below
the hypothesised value. What is the value of the test statistic? [2]
(c) What is the appropriate critical value at the 5% significance level? [1]
(d) Decide whether or not you would reject the hypothesis at the
5% significance level. [1]
(e) Using Figure 6 (Subsection 4.1), calculate the p-value given by the
hypothesis test. [3]
(f) Making reference to this p-value, what is the conclusion to be drawn
from the hypothesis test? How does this conclusion sit with the result
of part (d)? What is your overall conclusion in terms of weight change
after stopping smoking, based on these data?